The present invention relates to a connecting device in a hard disk drive (hereinafter, referred to as HDD), and more particularly to a connecting device that electrically connects a head installed on an actuator of the hard disk drive to a printed circuit substrate to enable transmission of signals between the head and the printed circuit substrate to minimize the transfer of force between the freely rotating actuator and the connecting device.
Generally, the hard disk drive used as either a main memory or, less frequently, an auxiliary memory device in a computer, includes a disk rotated at a high speed by a spindle motor, and an actuator having a magnetic head that reads and writes data recorded on tracks of the disk.
The actuator is mounted upon a bearing that is rotatable about a pivot positioned at a center portion of the actuator. As a bobbin and a coil are positioned at one end of the actuator to move under the control of a voice coil motor, the magnetic head is positioned at the other end of the actuator to move at both ends of the disk, thereby reading and writing data on tracks of the disk. Then, the magnetic head being moved at both surfaces of the disk, which is installed at a leading end of head gimbals, moves while maintaining a minute air gap between the head and the surface of the disk created by an upward force produced between the surface of the disk and the magnetic head as the disk rotates at a high speed.
When the hard disk drive stops or power to the spindle motor is turned off, the actuator is mounted to move to a parking zone located at an inner portion of the disk. When the power to the spindle motor of the hard disk drive is turned off, the actuator is adjusted to move inwardly, to thereby, in advance, prevent data recorded on the disk from being damaged due to contact between the magnetic head and the surface of the disk.
In the conventional hard disk drive operated as described above, a preamplifier is installed on one side of the actuator and a flexible printed circuit cable (e.g., a ribbon cable) is commonly used to transmit signals between the preamplifier and a printed circuit substrate mounted on the base of the hard disk drive. Often, in contemporary designs, the flexible printed circuit cable is doubled back upon itself or, alternatively, is provided with excessive length, in order to accommodate a complete sweep of the actuator across the surface of the disk; in some contemporary designs the cabling is twisted to mate with the printer circuit mounted upon a base of the disk drive. Consequently, movement of the actuator concomitantly, causes extension or compaction of the flexible printed circuit cable as the one end attached to the actuator is dragged alone to follow the rotation of the actuator. I have found that due to the very low coefficient of friction and the resultant extreme sensitivity of the actuator and its bearing to rotation within the plane defined by the surface of the disk, the flexible circuit generates a bias force effecting rotation of the actuator within that plane. In conventional drives the flexible printed circuit considers the generated bias force and then adjusts a value of an electric current that is applied to position the heads borne by the actuator when the magnetic head of the actuator searches for a specific track on the disk. I consider the creation of the bias force and the need to adjust the applied current to be major problems that detract from performance capability.